Multi-sensor tiled camera with flexible electronics for wafer inspection

ABSTRACT

Sensor units can be disposed in a support member. Each of the sensor units can include a folded flex board having a plurality of laminations and an aperture and a sensor disposed in the folded flex board such that the sensor is positioned over the aperture. The system can be used in broad band plasma inspection tools for semiconductor wafers.

FIELD OF THE DISCLOSURE

This disclosure relates to wafer inspection systems.

BACKGROUND OF THE DISCLOSURE

Evolution of the semiconductor manufacturing industry is placing greaterdemands on yield management and, in particular, on metrology andinspection systems. Critical dimensions continue to shrink, yet theindustry needs to decrease time for achieving high-yield, high-valueproduction. Minimizing the total time from detecting a yield problem tofixing it determines the return-on-investment for a semiconductormanufacturer.

Fabricating semiconductor devices, such as logic and memory devices,typically includes processing a semiconductor wafer using a large numberof fabrication processes to form various features and multiple levels ofthe semiconductor devices. For example, lithography is a semiconductorfabrication process that involves transferring a pattern from a reticleto a photoresist arranged on a semiconductor wafer. Additional examplesof semiconductor fabrication processes include, but are not limited to,chemical-mechanical polishing (CMP), etch, deposition, and ionimplantation. Multiple semiconductor devices may be fabricated in anarrangement on a single semiconductor wafer that are separated intoindividual semiconductor devices.

Inspection processes are used at various steps during semiconductormanufacturing to detect defects on wafers to promote higher yield in themanufacturing process and, thus, higher profits. Inspection has alwaysbeen an important part of fabricating semiconductor devices such asintegrated circuits (ICs). However, as the dimensions of semiconductordevices decrease, inspection becomes even more important to thesuccessful manufacture of acceptable semiconductor devices becausesmaller defects can cause the devices to fail. For instance, as thedimensions of semiconductor devices decrease, detection of defects ofdecreasing size has become necessary because even relatively smalldefects may cause unwanted aberrations in the semiconductor devices.

As design rules shrink, however, semiconductor manufacturing processesmay be operating closer to the limitation on the performance capabilityof the processes. In addition, smaller defects can have an impact on theelectrical parameters of the device as the design rules shrink, whichdrives more sensitive inspections. As design rules shrink, thepopulation of potentially yield-relevant defects detected by inspectiongrows dramatically, and the population of nuisance defects detected byinspection also increases dramatically. Therefore, more defects may bedetected on the wafers, and correcting the processes to eliminate all ofthe defects may be difficult and expensive. Determining which of thedefects actually have an effect on the electrical parameters of thedevices and the yield may allow process control methods to be focused onthose defects while largely ignoring others. Furthermore, at smallerdesign rules, process induced failures, in some cases, tend to besystematic. That is, process-induced failures tend to fail atpredetermined design patterns often repeated many times within thedesign. Elimination of spatially-systematic, electrically-relevantdefects can have an impact on yield.

Each new generation of wafer inspection tools brings higher sensitivityand higher throughput. Increasing the throughput requires fastercameras, but also brighter light sources that can place more photons ona wafer in less time. Even if brighter light sources can be produced,such brighter light sources can have reliability or cost drawbacks. Thecameras can help with this by increasing the number of time delayintegration (TDI) stages (e.g., pixels used to integrate light for agiven image) in a sensor. When the number of TDI stages is reached,multiple sensors can be tiled to better utilize the available field ofview.

Previously, a single carrier electronics device to support multiplesensors was used. The common carrier approach does not allow forflexible integration of each sensor. Furthermore, alignment is donewithout live feedback because the camera cannot operate duringalignment. This makes operation challenging. There also is a size limitas to how many sensors can be supported using a common carrier.

A detached sensor solution providing pig-tails or flexible media alsowas previously used. This cabling solution allow independent sensormechanical manipulation, but does not provide a high-speed solution thatcan support high throughput camera requirements (e.g., more than 3million lines per second). The number of connectors that need to be usedcan result in a larger volume implementation and reliability problemswith the connectors.

Therefore, an improved camera for inspection of semiconductor wafers isneeded.

BRIEF SUMMARY OF THE DISCLOSURE

A camera system is provided in a first embodiment. The camera systemcomprises a support member and a plurality of sensor units disposed inthe support member. Each of the sensor units includes a folded flexboard having a plurality of laminations, a sensor disposed in the foldedflex board, a high-density digitizer disposed in the folded flex board,and a field programmable gate array disposed in the folded flex board.The folded flex board defines an aperture. The sensor is disposed in thefolded flex board such that the sensor is positioned over the aperture.

The system can include, for example, three of the sensor units or six ofthe sensor units.

The sensor may be a time delay integration sensor.

The sensor can image 1536 pixels.

Two of the sensor units can be spaced apart by a distance from 5 mm to 7mm.

A land grid array for the sensor can have a pitch of 1 mm.

The camera system can further include a processor in electroniccommunication with the sensor units. The processor can be configured tostitch images from the sensors.

A broadband plasma inspection tool can include the camera system of thefirst embodiment.

A method is provided in a second embodiment. The method comprisesimaging a wafer with a plurality of sensor units disposed in a supportmember. Each of the sensor units includes a folded flex board having aplurality of laminations, a sensor disposed in the folded flex board, ahigh-density digitizer disposed in the folded flex board, and a fieldprogrammable gate array disposed in the folded flex board. The foldedflex board defines an aperture. The sensor is disposed in the foldedflex board such that the sensor is positioned over the aperture.

The method can further include stitching images from the sensors using aprocessor in electronic communication with the sensor units.

For example, three or six of the sensor units can be disposed in thesupport member.

DESCRIPTION OF THE DRAWINGS

For a fuller understanding of the nature and objects of the disclosure,reference should be made to the following detailed description taken inconjunction with the accompanying drawings, in which:

FIG. 1 illustrates a perspective view of an embodiment of a camerasystem in accordance with the present disclosure;

FIG. 2 illustrates an embodiment of a flex board in accordance with thepresent disclosure;

FIG. 3 illustrates an embodiment of the flex board of FIG. 2 whenfolded;

FIG. 4 is an optical representation of field of view;

FIG. 5 is a block diagram of a system that includes the camera system ofFIG. 1; and

FIG. 6 is a flowchart of an embodiment of a method in accordance withthe present disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

Although claimed subject matter will be described in terms of certainembodiments, other embodiments, including embodiments that do notprovide all of the benefits and features set forth herein, are alsowithin the scope of this disclosure. Various structural, logical,process step, and electronic changes may be made without departing fromthe scope of the disclosure. Accordingly, the scope of the disclosure isdefined only by reference to the appended claims.

Embodiments disclosed herein are directed to a camera architecture thatsupports multi-sensor integration in a single camera system withflexible electronics to allow optimal field of view utilization. Thiscan maximize the light produced in tool. Many degrees of freedom arerequired for each sensor to support mechanical integration andindividual alignment for optimal optical performance. Flexibleelectronics can provide mechanical independence for the individualsensors in tiled cameras while providing high quality substrate forhigh-speed electronics, chips, and interconnects. In the modularapproach disclosed herein, every tile is considered a standalone camera.All electronic circuits required to operate each individual sensor areincluded in a tile block. The architecture decouples the opto-mechanicalaspects of the design from the electronics required to operate thesensor. This allows full camera operation during individual alignmentprocess.

FIG. 1 illustrates a perspective view of an embodiment of a camerasystem 100. FIG. 2 illustrates an embodiment of a flex board 103. FIG. 3illustrates an embodiment of the flex board 103 of FIG. 2 when folded.As seen in FIG. 1, the camera system 100 includes a plurality of sensorunits 101 in a support member 102. Each sensor unit 101 includes afolded flex board 103 with laminations 104, such as that illustrated inFIG. 2. The laminations 104 may extend to or into rigid sections of thefolded flex board 103. The laminations 104 may be internal layers of theflex board 103 that are laminated with rigid cores from the rigidsections of the flex board 103. For example, the laminations 104 canfold along the dotted line in FIG. 2 or elsewhere on the laminations104. The flex board 103 also defines an aperture 105.

As seen in FIG. 1, a sensor 106 is disposed in the folded flex board 103such that the sensor 106 is positioned over the aperture 105. The sensor106 can be held to the aperture 105 using a mechanical interposerbetween the sensor package and rigid sections of the folded flex board103 (e.g., land grid array (LGA) interfaces). In an example, themechanical interposer can include approximately 2000 spring-basedcontacts to bridge across both LGA patterns. The assembly may be held incompression by screws from a front plate and a backing or pressure plateon an opposite side.

The sensor 106 can be a TDI sensor or another type of sensor. An LGA forthe sensor 106 can have a pitch of 1 mm or other values.

In an instance, the sensor 106 can image 1536 pixels. The sensor 106 canbe configured to image other ranges of pixels, and this is merely oneexample.

The sensor units 101 each also can include a high-density digitizer 107and a field programmable gate array 108 disposed in the folded flexboard 103. In an instance, the high-density digitizer 107 is part of thesensor 106. Thus, all the electronics to operate the sensor 106 can beincluded in the folded flex board 103. All sensor control (e.g., timing,gate driving) and processing (e.g., image calibration) electronics maybe contained in or around the aperture 105 so the individual sensor 106operation is contained in a single sensor unit 101.

Rigid flex technology with a high layer count can be used for the foldedflex board 103, which can enable the compact form. In an instance, theflex cores of the folded flex board 103 are made of PYRALUX AP fromDuPont, which is a flexible circuit material that includes an allpolyimide, double-sided, copper-clad laminate, and the rigid cores arestandard 370HR board material. Other materials for the flex cores orrigid cores are possible. All cores can be laminated together and theparts that only contain flex cores may be flexible. In an instance, theflex cores are not glued together in what is commonly known as “openbook” design to allow for a small bending radius and better flexibility.The number of layers, the number of vias, and the size of the vias canincrease complexity of fabrication for the folded flex board 103.

As seen in FIG. 1, three sensor units 101 can be included in the camerasystem 100. In another instance, the camera system 100 can include sixof the sensor units 101. Other numbers of sensor units 101 are possible.For example, four or five sensor units 101 can be used.

While illustrated as adjacent, the sensor units 101 can be spaced apartby a distance from 5 mm to 7 mm.

FIG. 4 is an optical representation of field of view. Previously, twocameras were used. This is shown by the two vertical rectangles 109. Thespacing of sensor units was constrained by the second camera (i.e., thesecond vertical rectangle 109) because all parts of the field of view inFIG. 4 need to be imaged. Now, six sensors 106 can be used. For example,two camera systems with three sensors 106 each can be used, but othernumbers of sensors 106 are possible if there is no scanning gap. Thesensors 106 disclosed herein have an overlap (e.g., an image is detectedby two or more sensors) to stitch the images together. This providesbetter light utilization because with six sensors 106 more than twicethe amount of light is imaged in the outer circle of FIG. 4 during theswath.

Tiles (e.g., sensors) can be laid out precisely to optimize imageperformance. This layout can create challenging electromechanicalrequirements for tile (e.g., individual sensor) package design and tilecarrier board (e.g., flex board). This design minimizes the light wasted(e.g., not collected) and has no gaps in the swathing of the TDI sensor.There may be overlap between tiles to put the image back together.

There may only be approximately 6 mm of space between sensor packages.Smaller sensors, such as 1024 pixel sensors, may be used. For example, a512 pixel sensor may be used and may allow more sensors to be included.These smaller sensors may be configured to have a package or routingspace overhead to fit into camera system 100.

A larger sensor may be challenging to implement because the larger thesensor then the larger the space between sensor packages. Sensor yielddecreases as the sensor increases in size, which impacts waferoccupation on the wafer used to produce the sensors.

The modular implementation disclosed herein allows individual mechanicalmanipulation while using camera to get live images. A sensor can beconnected to a motherboard by a single connector in a flex circuit. Thisallows image collection during tile alignment. The embodiments disclosedherein can provide high reliability because multiple connectors areavoided when using a rigid-flex circuit board approach. Multipleconnectors generally provide a point of failure.

Embodiments disclosed herein also provide a high-quality substrate inthe form of the flex board 103 to sustain high-speed operation.Connector or signal breaks in the flex board 103 between the variousrigid sections may be reduced or eliminated.

10 Gbps links can operate in this substrate. The tile carrier boardstack-up can combine flex cores with laser drilled micro-vias that allowhigh quality designs for 10 Gbps links. Micro-vias can enable 10 Grouting without via stubs.

By eliminating connectors, the embodiments disclosed herein are compact.When a cable connector solution is used, there can be a problem reducingthe number of pins (e.g., more than 2000 connections per sensor) withoutthe connectors occupying extensive space.

FIG. 5 is a block diagram of a system that includes the camera system ofFIG. 1. The system 200 includes optical based subsystem 201. In general,the optical based subsystem 201 is configured for generating opticalbased output for a specimen 202 by directing light to (or scanning lightover) and detecting light from the specimen 202. In one embodiment, thespecimen 202 includes a wafer. The wafer may include any wafer known inthe art. In another embodiment, the specimen includes a reticle. Thereticle may include any reticle known in the art.

In the embodiment of the system 200 shown in FIG. 5, optical basedsubsystem 201 includes an illumination subsystem configured to directlight to specimen 202. The illumination subsystem includes at least onelight source. For example, as shown in FIG. 5, the illuminationsubsystem includes light source 203. In one embodiment, the illuminationsubsystem is configured to direct the light to the specimen 202 at oneor more angles of incidence, which may include one or more obliqueangles and/or one or more normal angles. For example, as shown in FIG.5, light from light source 203 is directed through optical element 204and then lens 205 to specimen 202 at an oblique angle of incidence. Theoblique angle of incidence may include any suitable oblique angle ofincidence, which may vary depending on, for instance, characteristics ofthe specimen 202.

The optical based subsystem 201 may be configured to direct the light tothe specimen 202 at different angles of incidence at different times.For example, the optical based subsystem 201 may be configured to alterone or more characteristics of one or more elements of the illuminationsubsystem such that the light can be directed to the specimen 202 at anangle of incidence that is different than that shown in FIG. 5. In onesuch example, the optical based subsystem 201 may be configured to movelight source 203, optical element 204, and lens 205 such that the lightis directed to the specimen 202 at a different oblique angle ofincidence or a normal (or near normal) angle of incidence.

In some instances, the optical based subsystem 201 may be configured todirect light to the specimen 202 at more than one angle of incidence atthe same time. For example, the illumination subsystem may include morethan one illumination channel, one of the illumination channels mayinclude light source 203, optical element 204, and lens 205 as shown inFIG. 5 and another of the illumination channels (not shown) may includesimilar elements, which may be configured differently or the same, ormay include at least a light source and possibly one or more othercomponents such as those described further herein. If such light isdirected to the specimen at the same time as the other light, one ormore characteristics (e.g., wavelength, polarization, etc.) of the lightdirected to the specimen 202 at different angles of incidence may bedifferent such that light resulting from illumination of the specimen202 at the different angles of incidence can be discriminated from eachother at the detector(s).

In another instance, the illumination subsystem may include only onelight source (e.g., light source 203 shown in FIG. 5) and light from thelight source may be separated into different optical paths (e.g., basedon wavelength, polarization, etc.) by one or more optical elements (notshown) of the illumination subsystem. Light in each of the differentoptical paths may then be directed to the specimen 202. Multipleillumination channels may be configured to direct light to the specimen202 at the same time or at different times (e.g., when differentillumination channels are used to sequentially illuminate the specimen).In another instance, the same illumination channel may be configured todirect light to the specimen 202 with different characteristics atdifferent times. For example, in some instances, optical element 204 maybe configured as a spectral filter and the properties of the spectralfilter can be changed in a variety of different ways (e.g., by swappingout the spectral filter) such that different wavelengths of light can bedirected to the specimen 202 at different times. The illuminationsubsystem may have any other suitable configuration known in the art fordirecting the light having different or the same characteristics to thespecimen 202 at different or the same angles of incidence sequentiallyor simultaneously.

In one embodiment, light source 203 may include a broadband plasma (BBP)source, and the system 200 is a BBP inspection tool. In this manner, thelight generated by the light source 203 and directed to the specimen 202may include broadband light. However, the light source may include anyother suitable light source such as a laser. The laser may include anysuitable laser known in the art and may be configured to generate lightat any suitable wavelength or wavelengths known in the art. In addition,the laser may be configured to generate light that is monochromatic ornearly-monochromatic. In this manner, the laser may be a narrowbandlaser. The light source 203 may also include a polychromatic lightsource that generates light at multiple discrete wavelengths orwavebands.

Light from optical element 204 may be focused onto specimen 202 by lens205. Although lens 205 is shown in FIG. 5 as a single refractive opticalelement, it is to be understood that, in practice, lens 205 may includea number of refractive and/or reflective optical elements that incombination focus the light from the optical element to the specimen.The illumination subsystem shown in FIG. 5 and described herein mayinclude any other suitable optical elements (not shown). Examples ofsuch optical elements include, but are not limited to, polarizingcomponent(s), spectral filter(s), spatial filter(s), reflective opticalelement(s), apodizer(s), beam splitter(s) (such as beam splitter 213),aperture(s), and the like, which may include any such suitable opticalelements known in the art. In addition, the optical based subsystem 201may be configured to alter one or more of the elements of theillumination subsystem based on the type of illumination to be used forgenerating the optical based output.

The optical based subsystem 201 may also include a scanning subsystemconfigured to cause the light to be scanned over the specimen 202. Forexample, the optical based subsystem 201 may include stage 206 on whichspecimen 202 is disposed during optical based output generation. Thescanning subsystem may include any suitable mechanical and/or roboticassembly (that includes stage 206) that can be configured to move thespecimen 202 such that the light can be scanned over the specimen 202.In addition, or alternatively, the optical based subsystem 201 may beconfigured such that one or more optical elements of the optical basedsubsystem 201 perform some scanning of the light over the specimen 202.The light may be scanned over the specimen 202 in any suitable fashionsuch as in a serpentine-like path or in a spiral path.

The optical based subsystem 201 further includes one or more detectionchannels. At least one of the one or more detection channels includes adetector configured to detect light from the specimen 202 due toillumination of the specimen 202 by the subsystem and to generate outputresponsive to the detected light. For example, the optical basedsubsystem 201 shown in FIG. 5 includes two detection channels, oneformed by collector 207, element 208, and detector 209 and anotherformed by collector 210, element 211, and camera system 100. As shown inFIG. 5, the two detection channels are configured to collect and detectlight at different angles of collection. In some instances, bothdetection channels are configured to detect scattered light, and thedetection channels are configured to detect tight that is scattered atdifferent angles from the specimen 202. However, one or more of thedetection channels may be configured to detect another type of lightfrom the specimen 202 (e.g., reflected light).

As further shown in FIG. 5, both detection channels are shown positionedin the plane of the paper and the illumination subsystem is also shownpositioned in the plane of the paper. Therefore, in this embodiment,both detection channels are positioned in (e.g., centered in) the planeof incidence. However, one or more of the detection channels may bepositioned out of the plane of incidence. For example, the detectionchannel formed by collector 210, element 211, and camera system 100 maybe configured to collect and detect light that is scattered out of theplane of incidence. Therefore, such a detection channel may be commonlyreferred to as a “side” channel, and such a side channel may be centeredin a plane that is substantially perpendicular to the plane ofincidence.

Although FIG. 5 shows an embodiment of the optical based subsystem 201that includes two detection channels, the optical based subsystem 201may include a different number of detection channels (e.g., only onedetection channel or two or more detection channels). In one suchinstance, the detection channel formed by collector 210, element 211,and camera system 100 may form one side channel as described above, andthe optical based subsystem 201 may include an additional detectionchannel (not shown) formed as another side channel that is positioned onthe opposite side of the plane of incidence. Therefore, the opticalbased subsystem 201 may include the detection channel that includescollector 207, element 208, and detector 209 and that is centered in theplane of incidence and configured to collect and detect light atscattering angle(s) that are at or close to normal to the specimen 202surface. This detection channel may therefore be commonly referred to asa “top” channel, and the optical based subsystem 201 may also includetwo or more side channels configured as described above. As such, theoptical based subsystem 201 may include at least three channels (i.e.,one top channel and two side channels), and each of the at least threechannels has its own collector, each of which is configured to collectlight at different scattering angles than each of the other collectors.

As described further above, each of the detection channels included inthe optical based subsystem 201 may be configured to detect scatteredlight. Therefore, the optical based subsystem 201 shown in FIG. 5 may beconfigured for dark field (DF) output generation for specimens 202.However, the optical based subsystem 201 may also or alternativelyinclude detection channel(s) that are configured for bright field (BF)output generation for specimens 202. In other words, the optical basedsubsystem 201 may include at least one detection channel that isconfigured to detect light specularly reflected from the specimen 202.Therefore, the optical based subsystems 201 described herein may beconfigured for only DF, only BF, or both DF and BF imaging. Althougheach of the collectors are shown in FIG. 5 as single refractive opticalelements, it is to be understood that each of the collectors may includeone or more refractive optical die(s) and/or one or more reflectiveoptical element(s).

The one or more detection channels may include any suitable detectorsknown in the art. For example, the detectors may includephoto-multiplier tubes (PMTs), charge coupled devices (CCDs), TDIcameras (such as those included in the camera system 100 of FIG. 1), andany other suitable detectors known in the art. The detectors may alsoinclude non-imaging detectors or imaging detectors. In this manner, ifthe detectors are non-imaging detectors, each of the detectors may beconfigured to detect certain characteristics of the scattered light suchas intensity but may not be configured to detect such characteristics asa function of position within the imaging plane. As such, the outputthat is generated by each of the detectors included in each of thedetection channels of the optical based subsystem may be signals ordata, but not image signals or image data. In such instances, aprocessor such as processor 214 may be configured to generate images ofthe specimen 202 from the non-imaging output of the detectors. However,in other instances, the detectors may be configured as imaging detectorsthat are configured to generate imaging signals or image data.Therefore, the optical based subsystem may be configured to generateoptical images or other optical based output described herein in anumber of ways.

It is noted that FIG. 5 is provided herein to generally illustrate aconfiguration of an optical based subsystem 201 that may be included inthe system embodiments described herein or that may generate opticalbased output that is used by the system embodiments described herein.The optical based subsystem 201 configuration described herein may bealtered to optimize the performance of the optical based subsystem 201as is normally performed when designing a commercial output acquisitionsystem. In addition, the systems described herein may be implementedusing an existing system (e.g., by adding functionality described hereinto an existing system). For some such systems, the methods describedherein may be provided as optional functionality of the system (e.g., inaddition to other functionality of the system). Alternatively, thesystem described herein may be designed as a completely new system.

The processor 214 may be coupled to the components of the system 200 inany suitable manner (e.g., via one or more transmission media, which mayinclude wired and/or wireless transmission media) such that theprocessor 214 can receive output. The processor 214 may be configured toperform a number of functions using the output. The system 200 canreceive instructions or other information from the processor 214. Theprocessor 214 and/or the electronic data storage unit 215 optionally maybe in electronic communication with a wafer inspection tool, a wafermetrology tool, or a wafer review tool (not illustrated) to receiveadditional information or send instructions. For example, the processor214 and/or the electronic data storage unit 215 can be in electroniccommunication with a scanning electron microscope (SEM).

The processor 214, other system(s), or other subsystem(s) describedherein may be part of various systems, including a personal computersystem, image computer, mainframe computer system, workstation, networkappliance, internet appliance, or other device. The subsystem(s) orsystem(s) may also include any suitable processor known in the art, suchas a parallel processor. In addition, the subsystem(s) or system(s) mayinclude a platform with high-speed processing and software, either as astandalone or a networked tool.

The processor 214 and electronic data storage unit 215 may be disposedin or otherwise part of the system 200 or another device. In an example,the processor 214 and electronic data storage unit 215 may be part of astandalone control unit or in a centralized quality control unit.Multiple processors 214 or electronic data storage units 215 may beused.

The processor 214 may be implemented in practice by any combination ofhardware, software, and firmware. Also, its functions as describedherein may be performed by one unit, or divided up among differentcomponents, each of which may be implemented in turn by any combinationof hardware, software and firmware. Program code or instructions for theprocessor 214 to implement various methods and functions may be storedin readable storage media, such as a memory in the electronic datastorage unit 215 or other memory.

If the system 200 includes more than one processor 214, then thedifferent subsystems may be coupled to each other such that images,data, information, instructions, etc. can be sent between thesubsystems. For example, one subsystem may be coupled to additionalsubsystem(s) by any suitable transmission media, which may include anysuitable wired and/or wireless transmission media known in the art. Twoor more of such subsystems may also be effectively coupled by a sharedcomputer-readable storage medium (not shown).

The processor 214 may be configured to perform a number of functionsusing the output of the system 200 or other output. For instance, theprocessor 214 may be configured to send the output to an electronic datastorage unit 215 or another storage medium. The processor 214 may befurther configured as described herein.

The processor 214 may be configured according to any of the embodimentsdescribed herein. The processor 214 also may be configured to performother functions or additional steps using the output of the system 200or using images or data from other sources.

Various steps, functions, and/or operations of system 200 and themethods disclosed herein are carried out by one or more of thefollowing: electronic circuits, logic gates, multiplexers, programmablelogic devices, ASICs, analog or digital controls/switches,microcontrollers, or computing systems. Program instructionsimplementing methods such as those described herein may be transmittedover or stored on carrier medium. The carrier medium may include astorage medium such as a read-only memory, a random access memory, amagnetic or optical disk, a non-volatile memory, a solid state memory, amagnetic tape, and the like. A carrier medium may include a transmissionmedium such as a wire, cable, or wireless transmission link. Forinstance, the various steps described throughout the present disclosuremay be carried out by a single processor 214 or, alternatively, multipleprocessors 214. Moreover, different sub-systems of the system 200 mayinclude one or more computing or logic systems. Therefore, the abovedescription should not be interpreted as a limitation on the presentdisclosure but merely an illustration.

In an instance, the processor 214 is in communication with the system200. The processor 214 can be configured to stitch images from thesensors in the camera system 100.

An additional embodiment relates to a non-transitory computer-readablemedium storing program instructions executable on a controller forperforming a computer-implemented method for determining a height of anilluminated region on a surface of a specimen 202, as disclosed herein.In particular, as shown in FIG. 5, electronic data storage unit 215 orother storage medium may contain non-transitory computer-readable mediumthat includes program instructions executable on the processor 214. Thecomputer-implemented method may include any step(s) of any method(s)described herein, including method 300.

Program instructions implementing methods such as those described hereinmay be stored on computer-readable medium, such as in the electronicdata storage unit 215 or other storage medium. The computer-readablemedium may be a storage medium such as a magnetic or optical disk, amagnetic tape, or any other suitable non-transitory computer-readablemedium known in the art.

The program instructions may be implemented in any of various ways,including procedure-based techniques, component-based techniques, and/orobject-oriented techniques, among others. For example, the programinstructions may be implemented using ActiveX controls, C++ objects,JavaBeans, Microsoft Foundation Classes (MFC), Streaming SIMD Extension(SSE), or other technologies or methodologies, as desired.

FIG. 6 is a flowchart of an embodiment of a method 300. At 301, a waferis imaged with sensor units. Each of the sensor units includes a foldedflex board having laminations and defining an aperture; a sensordisposed in the folded flex board such that the sensor is positionedover the aperture, a high-density digitizer disposed in the folded flexboard; and a field programmable gate array disposed in the folded flexboard. There may be, for example, three or six sensor units disposed inthe support member.

At 302, images from the sensors are stitched together using a processorin electronic communication with the sensor units.

Each of the steps of the method may be performed as described herein.The methods also may include any other step(s) that can be performed bythe processor and/or computer subsystem(s) or system(s) describedherein. The steps can be performed by one or more computer systems,which may be configured according to any of the embodiments describedherein. In addition, the methods described above may be performed by anyof the system embodiments described herein.

Although the present disclosure has been described with respect to oneor more particular embodiments, it will be understood that otherembodiments of the present disclosure may be made without departing fromthe scope of the present disclosure. Hence, the present disclosure isdeemed limited only by the appended claims and the reasonableinterpretation thereof.

What is claimed is:
 1. A camera system comprising: a support member; anda plurality of sensor units disposed in the support member, wherein eachof the sensor units includes: a folded flex board having a plurality oflaminations, wherein the folded flex board defines an aperture; a sensordisposed in the folded flex board such that the sensor is positionedover the aperture; a high-density digitizer disposed in the folded flexboard; and a field programmable gate array disposed in the folded flexboard.
 2. The camera system of claim 1, wherein the system includesthree of the sensor units.
 3. The camera system of claim 1, wherein thesystem includes six of the sensor units.
 4. The camera system of claim1, wherein the sensor is a time delay integration sensor.
 5. The camerasystem of claim 1, wherein the sensor images 1536 pixels.
 6. The camerasystem of claim 1, wherein two of the sensor units are spaced apart by adistance from 5 mm to 7 mm.
 7. The camera system of claim 1, wherein aland grid array for the sensor has a pitch of 1 mm.
 8. The camera systemof claim 1, further comprising a processor in electronic communicationwith the sensor units, wherein the processor is configured to stitchimages from the sensors.
 9. A broadband plasma inspection tool thatincludes the camera system of claim
 1. 10. A method comprising: imaginga wafer with a plurality of sensor units disposed in a support member,wherein each of the sensor units includes: a folded flex board having aplurality of laminations, wherein the folded flex board defines anaperture; a sensor disposed in the folded flex board such that thesensor is positioned over the aperture; a high-density digitizerdisposed in the folded flex board; and a field programmable gate arraydisposed in the folded flex board.
 11. The method of claim 10, furthercomprising stitching images from the sensors using a processor inelectronic communication with the sensor units.
 12. The method of claim10, wherein three of the sensor units are disposed in the supportmember.
 13. The method of claim 10, wherein six of the sensor units aredisposed in the support member.